Ice cube making machine

ABSTRACT

An automatic ice cube making machine of the type having a plurality of open bottom cells fixed adjacent an evaporator with a moveable closure plate operated by a motor to move the plate from an ice forming cell-closure position to an ice discharge position. The improvement residing in the control circuitry utilizing two separate thermo static switches responsive to the evaporator temperature for moving the closure plate.

United States Paten Sayles ICE CUBE MAKING MACHINE 5] Nov. 26, 19743,277,661 10/1966 Dwyer ..62/348X Primary Examiner william E. WaynerAttorney, Agent, or FirmAmster and Rothstein [5 7] ABSTRACT An automaticice cube making machine of the type having a plurality of open bottomcells fixed adjacent an evaporator with a moveable closure plateoperated by a motor to move the plate from an ice forming cellclosureposition to an ice discharge position. The improvement residing in thecontrol circuitry utilizing two separate thermo static switchesresponsive to the evaporator temperature for moving the closure plate.

15 Claims, 7 Drawing Figures PATENH HUVZBIQM 185(LOU5 SHEET F QINVENTOR. WILLIAM E SAYLES ATTORNEYS PATENTL 3,8501b0O5 saw an?INVENTOR. WILLIAM F. SAYLES ATTORNEYS NEIL, $21M 2 3 HM WEN 3 @F aATTORNEYS ICE CUBE MAKING MACHINE This invention relates torefrigeration equipment and, more particularly, to improved apparatusfor furnishing uniformly shaped ice cubes more rapidly and moreefficiently than in the past.

In recent years, the demand for refrigeration equipment of all kinds haswitnessed a dramatic surge upwards. Emphasis has often been placed onthe application of such equipment to the requirements of the individualconsumer. Thus, with respect to the preparation of ice cubes, thedomestic needs of the consumer, as well as the more commerciallyoriented needs of industry, have been given attention by manufacturersand designers. It is, for example, well known that ice cube makingequipment is required in varying degrees in home refrigerators.Moreover, many homes even have their own separate machines to providefor their greater individual needs. Then, too, commercial ice cubemaking equipment is available for very high demands such as incoin-operated public apparatus, restaurant equipment, etc.

While various types of equipment are currently available to fulfill mostof these requirements, such as equipment has not proven altogethersatisfactory. All too frequently, the ice cube making procedures are tootime-consuming. Accordingly, where rapid turnover and high demand arerequired, present systems are often inadequate. Furthermore, currentlyavailable equipment often fails to produce uniform ice cubes as toclarity, the desired cubical shape, frozen consistency, etc. Thesefailings are often based on the unavailability of adequate means tocontrol the freezing and harvesting" cycles. Thus, the prior art oftenuses weight-responsive control equipment to detect the moment when,based on runoff from the ice cube freezing containers, harvesting shouldcommence. Such equipment, which is generally spring-loaded, is notsufficiently sensitive to allow for the accurate termination of thefreezing cycle and thus the commencement of the harvesting cycle.

And where the prior art has recognized that thermostatically controlledinstrumentation would be desirable, such equipment has only been addedin a passive manner in conjunction with the spring-loaded equipmentpreviously adverted to. Thus, in one prior art arrangement, when thewater rises to a predetermined level in the storage tank, the waterlevel in a controlling pilot tank similarly rises. When the pilot tanklevel is high enough to trigger a weight-responsive control, a switch isactivated which then cuts in a circuit controlled by a thermostat.However, the great advantages of thermostatic control are not realizedin the prior art circuitry due to the internal dependence onweightresponsive and spring-loaded equipment. Due to factors such ashumidity, temperature variations, etc., it has been found that suchequipment is generally unde sirable in terms of controlling ice cubemaking machines.

Also contributing to the time-consuming nature of ice cube makingaccording to the prior art is the failure to retain as much as possibleof the water which is introduced into the system at any time. Forexample, several prior art machines include a drainage cycle whichserves to completely dispose of stored water during each ice cubeharvesting cycle. Accordingly, each subsequent charge" of water must becorrespondingly greater to compensate for this cyclical water loss.

Moreover, while the prior art systems generally do .re-

tain and recirculate the water which is introduced into the ice cubemaking receptacles and does not initially freeze therein, these systemsmake no effort to retain the cleansing water which is passed over thefreezing plate in such systems. Thus, following a harvesting cycle, theplate is cleaned of any ice which may remain thereon and the prior artthen disposes of this excess water. It has been found that the retentionof this water and its introduction into the recirculation system, thusallowing for its subsequent freezing inthe ice cube receptacles,significantly reduces the time required for the freezing cycle.

' It is therefore an object of this invention to furnish an improved icecube making machine to obviate one or more of the aforesaiddifficulties.

It is also an object of this invention to furnish equipment'for markedlyreducing the time required for the freezing cycle in an ice cube makingarrangement, thereby resulting in increased ice cube production.

It is also an object of this invention to operate an ice cube makingmachine in a more efficient manner, thus requiring significantly reducedquantities of water to produce the same numbers of ice cubes as machineshave produced heretofore.

It is still another object of this invention to produce moresatisfactory ice cubes in terms of their shape, size, weight, clarity,etc.

It is a further object of this invention to provide more efficient andaccurate control arrangements to govern the cycles producing ice cubesof desired shapes.

ln one particular illustrative embodiment of the principles of thisinvention, an ice cube making machine is formed with a hinged storagetank assembly which is capable of dropping into a lower inclinedposition during the ice cube harvesting" cycle, and. under the influenceof motorized control, is returned to a substantially horizontal positionduring the ice cube making cycle. Referring to these two cycles, the icecube making cycle is initiated when the hinged tank assembly is returnedto the horizontal position. At this time, a horizontal freezing plateforms the upper surface of the assembly and acts as a bottom closure fora grid of openbottom ice cube receptacles in a mounted evaporator andfreezing assembly. Coolant coils are located conveniently above the icecube making receptacles and when the ice cube making cycle hascommenced, the coolant flows through the coils under the influence of atypical compressor unit.

Also in response to the commencement of the .ice cube making cycle,water which has been stored in the reservoir at the lower portion of thetank storage assembly is introduced into a pump which is activated atthis time. The pump forces this water into a recirculating chamber whichcommunicates with a plurality of header tubes running the length of thefreezing plate. The pump pressure isadjusted so that thewater which isintroduced into these tubes below the freezing plate is forced upwardlyfrom the header tubes through small orifices in the plate intorespective ice cube freezing receptacles in the mounted evaporatorassembly previously referred to. Due to the quite cold environmentestablished by the coolant flowing through the freezing coils, most ofthe water thusly introduced into the ice cube freezing receptaclesadheres to the top and sides thereof and forms the shell of an ice cube;gradually, as more water is so introduced, the entire ice cube takesshape in each of the receptacles. Any water which does not initiallyadhere to the top or side walls of the freezing receptacles is guidedthrough appropriate additional recapturing orifices in the plate back tothe reservoir in the storage tank. This allows the water in thereservoir to remain at a relatively cool temperature with relation tosupply or main water which is generally used to charge the system (seebelow).

One advantageous aspect of the present ice cube making machine involvesthe use ofa thermostatic control to detect the precise moment when theice cubes have properly formed in their various receptacles. Generally,as previously referred to, the prior art would measure (e.g., weigh) thequantity of runoff water from the various receptacles (i.e., water whichhad not initially frozen) to indicate when the freezing cycle shouldterminate. However, as noted above, this is a relatively insensitivemeasuring technique and is not nearly as desirable as the thermostaticcontrol utilized herein. Accordingly, the thermostatic control isadjusted so that at the precise moment when the freezing environment isreduced to a temperature sufficiently low that substantially all thefreezing receptacles have ice cubes frozen therein, the freezing cyclewill be terminated, thus commencing the harvesting cycle.

In response to the activation ofthis thermostatic control, severaldevices are energized. initially, a circuit is closed for the activationof a reversible actuator motor which controls the positioning of thehinged storage tank and plate assembly. In this particular instance, themotor is activated so as to permit the assembly to assume its lower,inclined position. An appropriate selfoperated toggle switch is thenactivated to turn off the motor when the lower position is reached. Anactivating arm linked to the movement ofthe storage tank and plateassembly causes a "hot gas" solenoid in the path of the coolant toincrease the cross-sectional area of the entry to the coolant coils, andthe resultant unblocking causes the coolant" to act as a heating agentthroughout the coils of the evaporator assembly. Accordingly, as soon asthis solenoid is activated, the presence of the hot gas in the coilsbegins to dislodge (i.e., by slight melting) the ice cubes from theirfrozen positions within the ice cube receptacles. Since the plate hasbeen lowered so that it no longer forms the bottom of the receptacles,the ice cubes can fall by gravity and slide along the inclined plateinto an ice cube storage bin for collection.

The lowering of the hinged assembly also deactivates the water pump sothat during the harvesting cycle, no water is introduced into therecirculating system. However, some main water must be introduced intothe system in order to keep it functioning continuously. It is notedthat by eliminating the wasteful drain cycles typical of the prior art,the machine of this invention operates with substantially less water percycle. This water is generally introduced by means of a supply headerwhich runs the width of the freezing plate and is disposed somewhatabove it at the upper inclined portion thereof. A water solenoid isactivated by the lowering of the hinged assembly and a predeterminedcharge of water is introduced through the solenoid and into the supplyheader, whereupon the wter is gradually and continuously deposited atthe upper edge of the freezing plate. This water serves severalfunctions. Initially, it serves to replenish the water in the reservoirof the storage tank. This is achieved by the water dipping through therecapturing orifices in the freezing plate. In addition, however, thiswater serves to remove any iced portions from the freezing plate toavoid plate freezeup. This cleaning effect has often been disregarded byprior art systems and the water used therefor discarded when thecleaning is completed. However, the present invention makes use of thiscleaning water and retains it for use in the recirculation system. Thisis achieved in one illustrative embodiment of this invention by formingthe reservoir of the storage tank assembly with a protruding lip orcatch basin which retains this water as it flows off the plate (sincethe plate is in its inclined position). This water then mixes with thenormally stored water in the reservoir and since it is much cooler thanthat introduced from the main supply, and also because no water isdrained from the reservoir, significant increases in the speed of thefreezing cycle are achieved. Accordingly, the time required for thefreezing cycle is markedly reduced.

The thermostatic control of the freezing cycle previously referred to italso utilized to control the length of time of the harvesting cycle. Forexample, when the thermostatic control, having been previouslyappropriately adjusted, recognizes that a suitable high temperature hasbeen reached, this is established as the completion point of theharvesting cycle. This adjustment is made so that all ice cubes willhave previously been dislodged from their various receptacles andsufficient water has been added through the water solenoid to bothcleanse the freezing plate and to replenish the reservoir supply. Thus,when the thermostatic control operates in response to this highertemperature, the reversible actuator motor is activated so as to returnthe storage and tank assembly to its substantially horizontal position,at which point the self-operated toggle switch is thrown to stabilizethe assembly in this position. Once again, the horizontal freezing plateforms the bottom closure of the freezing grid receptacles.Simultaneously, the hot gas solenoid constricts the coolant passagewayso that the flowing gas can assume its cooling function. In addition,the water solenoid is deactivated, thereby terminating the entry of mainwater into the reservoir, and the water pump is again activated torecommence recirculation. Water is once again introduced into theplurality of header tubes below the surface of the freezing plate,forced upward through the appropriate orifices into the freezingreceptacles and the ice cube making or freezing cycle is againcommenced.

It is therefore a feature of an embodiment of this invention that an icecube making machine utilizes a reversible self-controlled actuator motorto position a storage tank assembly between an ice cube making positionand an ice cube harvesting position.

It is a further feature of an embodiment of this invention thattemperature-responsive means are utilized to control the respectivedurations of the ice cube making and harvesting cycles in an ice cubemaking machine.

Still another feature of an embodiment of this invention includesfacilities for retaining water utilized as an ice-removing agent andsubsequently introducing said water into a recirculating system during afreezing cycle.

The above brief description, as well as further objects, features andadvantages of the present invention, will be more fully appreciated byreference to the following detailed description of a presentlypreferred, but nonetheless illustrative embodiment demonstrating objectsand features of the invention, when taken in conjunction with theaccompanying drawing, wherein:

FIG. 1 is an overall perspective view of an ice cube making machine inaccordance with this invention, with the cover omitted to show a storageand tank assembly in an ice cube harvesting position;

FIG. 2 is an enlarged plan view of the freezing and evaporator assemblyof an ice cube making machine, including the freezing coils, andportions of the water recirculating and pumping apparatus shown inphantom;

FIG. 3 is a fragmentary and enlarged front view of an ice cube makingmachine indicating the ice cube harvesting position;

FIG. 4 is a fragmentary and enlarged front view, partly broken away andpartly in section, of the ice cube making machine in its ice cube makingor freezing position;

FIG. 5 is a fragmentary sectional view of the relationship between thefreezing coils, ice cube making receptacles, freezing plate and waterentry header tubes in the ice cube making arrangement of the invention;

FIG. 6 is a fragmentary sectional view, taken along the lines 6-6 ofFIG. 5 in the direction of the arrows; and

FIG. 7 is a schematic diagram of the wiring for the subject ice cubemaking machine.

A general perspective representation of the ice cube making machine ofthe present invention is given in FIG. I, where the cover has beemomitted in order to expose general portions of the inner mechanisms. Forexample, the overall machine 10 has an ice cube receiving bin 12 withseveral illustrative ice cubes 14 shown therein. The upper portion ofthe machine includes an evaporator and freezing assembly 16 havingconvoluted evaporator coils 18 above an upper surface 17 of a grid ofice cube freezing receptacles 19 (not shown in FIG. I, but see FIGS.3-6). The tank means and closure plate are illustrated as the storagetank and plate assembly 20 which is shown in FIG. I in the socalledharvesting" position where ice cubes can drop from the evaporatorassembly 16, onto the inclined surface of the plate 24 and thence intothe ice cube bin 12. Reference to FIG. 3 will indicate the enlarged andmore highly detailed version of the harvesting position. lncluded'in therendering of FIG. 1 are a reservoir 22 at the lower portion of theassembly 20 and a catch basin or lip 26 protruding past the end of theplate 24 to catch water flowing along the upper surface of plate 24after excess ice has been removed therefrom. With storage tank assembly20 in its inclined position as shown in FIG. 1, linking arm 30 is alsoin a relatively lower position such that toggle switch 34 is switched toactivate the hot gas solenoid 32 (see FIGS. 24) in a manner to be morefully described below. The assembly 20 is maintained in its loweredharvesting position by virtue of hinging at its upper end and by theconnection including link 36 and spring 38 to mounting plate 40 at theother end.

The plan view of FIG. 2 shows the evaporator coils l8 asthey aredisposed above the surface 17 of the evaporator assembly 16. Inaddition, aperture 17a are included in the upper surface 17 of theevaporator assembly in order to allow for the escape of air during theformation of ice cubes in receptacles 19 (see FIGS. 5 and 6), and topromote the ease of release of the ice cubes during the harvestingcycle. With reference to FIGS. 5 and 6, it is noted that during thefreezing cycle, water is pumped into header tubes 52 and thence upwardlyinto the ice cube freezing receptacles 19 through header orifices 24a inthe plate 24. Water then commences to adhere to the top and side wallsof the receptacles 19. The water which does not so adhere drips downthrough recapturing orifices 24b in the plate 24 and is accumulated inthe reservoir 22 in the storage and tank assembly 20. The relationshipbetween orifices l7a, 24a and 24b can best be appreciated by referenceto FIG. 2, by noting the broken away portion thereof indicating theorifices 24a and 24b.

Prior to a description of a typical operational cycle of the machine ofthe present invention, the functioning of various portions of thecontrol and circulating apparatus, including the recirculation meanswill now be described with reference to FIGS. 2, 3 and 4. In thisregard, the edge view of recirculation chamber 44 is shown in FIGS. 3and 4, while its plan view is presented in FIG. 2. Typically, the waterwhich is stored in reservoir 22 is circulated through conduit 46 to andunder the influence of water pump 28, and out therefrom through pipe 48to the recirculation chamber 44. During the ice cube freezing cycle(FIG. 4) the water is then forced from the recirculation chamber 44through the plurality of oval-shaped header tubes 52 (see FIG. 6) andthence upward through inlet apertures 24a into the various freezingreceptacles 19.

When the storage tank and plate'assembly 20 is in its inclined down"position shown in FIG. 3, it has been previously noted that the watersolenoid 54 is activated; this serves to deliver a charge of supplywater through connecting pipe 55 to a header 50. Water is then depositedfrom header tube 50 at the upper portion of plate 24, thereby flowingdownwardly along the inclined plate and cleaning any freeze-upconditions thereon. Moreover, the water in reservoir 22 is replenishedby the passage of such deposited water through the recapturing orifices24b in the plate 24. In addition, it is noted that the position of catchbasin 26 is such that any water reaching the edge of plate 24 will berecaptured within reservoir 22 by virtue of the provision of catch basinlip 26.

With respect to the supporting of storage tank and plate assembly 20, itis noted in FIGS. 3 and 4 that the entire assembly, including the waterpump 28, is piv oted at pin 53 on the left-hand support or mountingplate 51; the overall'assembly 20 is rigidly affixed to pivoted bracketmember 57, thereby allowing for relatively free movement of the assembly20 under the sole control of reversible actuator motor 70. For example,referring to FIG. 3, when the assembly 20 is in its lower extendedposition corresponding to the harvesting cycle ofthe machine, spring 38is extended between its link 36 and tie rod or pin 43 on the side plateof the assembly 20. The link 36, which is in turn pivoted at pin 41 onmounting plate 40, connects with arm 39 which serves to throw toggleswitch 42 and thereby deactivate the actuator motor when the assembly 20has been lowered to the position shown in FIG. 3. Similarly, when theactuator motor is energized so as to raise the assembly 20, theclockwise rotation of link 36 about pin 41 ultimately serves, upon lofsuch rotation, to again activate toggle switch 42 and therebyde-energize the actuator motor 70 when the assembly has been raised toits substantially horizontal position. The compressed position of link36, spring 38 and arm 39 which then exists is shown partially in phantomin. FIG. 4.

CYCLICAL OPERATION FIGS. 3 AND 4 When the machine of the presentinvention is in the position indicated in FIG. 3, the ice cubes 14 shownfalling off the plate 24 and towards the bin 12 has just been dislodgedfrom their various ice cube making receptacles 19. This is the.harvesting position of the machine. While the ice cubes 14 are being soharvested, relatively hot gas is being passed through the evaporatorcoils 18 resulting in the dislodging of the ice cubes 14 from theirreceptacles 19. The passage of hot gas through the coils l8 continuesuntil the previously adjusted thermostatic motor control 56 and cyclecontrol 94 determine that the temperature in the vicinity of theparitions 19 is sufficiently high so that all of the ice cubes will havebeen harvested. Until that time arrives, a water charge is beingintroduced under the influence of water solenoid 54 and through pipe 55to header 50, whereupon the water is discharged onto the plate 24 toprovide for cleaning thereof and to replenish, through orifices 24b(FIG. 2), additional water to replenish that in storage reservoir 22. Inaccordance with the present invention, it is noted that any water whichflows down the plate 24 and which does not pass to the reservoir portion22 through the orifices 24b is nevertheless recaptured by the reservoir22 by virtue of catch lip 26. The prior art machines generally disposedof this cleaning water, therey impairing their efficiency. As previouslynoted, at this time the water pump 28 is in its of condition, so that nowater is being recirculated from reservoir 22 to recirculation chamber44. Finally, actuator motor 70 has been deactivated by the action of rod39 in switching toggle switch 42 after the assembly 20 was lowered tothe position shown in FIG. 3.

1. Ice Cube Making Cycle The ice cube making cycle commences when thethermostatic feeler 58, which has been previously calibrated inconjunction with its motor control 56 (which may be any of severalcommercially available types such as Ranco lnc.s Type All), indicatesthat its high limit has been reached and that accordingly, all ice cubeswhich were previously frozen in receptacles 19 in the assembly 16 havebeen dislodged therefrom. This calibration can be made, for example, onthe basis of several trial runs, whereby the temperature at which allthe ice cubes are harvested is determined. Considering FIGS. 3 and 4together with the electrical wiring diagram of FIG. 7, the higl1"activation of thermostatic control 56 closes a circuit between terminals56a and 56c by virtue of arm 56. (Similar adjustment of thermostaticcycle control 94 causes arm 94 to contact free terminal 94b.) Arm 56 nowcompletes a circuit for the raising of storage and plate assembly 20,that circuit being traceable from a source of positive potential,through closed closed switch 60, to terminal 64, along conductor 66,terminal 56a, arm 56, terminal 560, conductor 74, representative arm 42aof actuating toggle switch 42 (left position), terminal 72a, terminal70a, a first winding of actuator motor 70 (not shown), common terminal70b and over conductor 76 to a source of negative potential. In responseto the activation of this winding of actuator motor 70, the storage andplate assembly 20 is gradually raised towards the position shown in FIG.4, i.e., the ice cube making position. When the assembly 20 has beenraised to a substantially horizontal position (FIG. 4), the link 36deflects the toggle switch 42 and thereby deactivates the motor 70. Withreference to the electrical diagram of FIG. 7, the arms 42a and 42b oftoggle switch 42 are returned to their right positions. Since there ispresently no complete circuit to the lowering" winding (not shown) ofactuator motor between terminals 70b 700, the motor 70 remains off atthis time, thereby stabilizing the assembly 20 in its horizontalposition for the ice cube making cycle.

When the horizontal position of the assembly 20 shown in FIG. 4 has beenreached, the water solenoid 54 is deactivated to terminate theintroduction of supply water to the system, the pump 28 is turned on totransport water from reservoir 22 to recirculation chamber 44, and thehot gas solenoid 32 is deactivated so as to allow the refrigerant toperform the desired cooling function in the evaporator coils 18. Theseoperations are achieved as follows: I-Iot gas solenoid 32 is deactivatedin response to the upward movement of connecting arm 30 so thatspringloaded toggle switch 34 can return to its up position. Since thearm 30 is coupled to the assembly 20 by means of slotted member 31 (seeFIGS. 1 and 3) and has collar 33 rigidly mounted on it, the arm movesupwardly when slotted member 31 contacts collar 33 as the assembly 20 israised. The switch 34 returns to its up position, whereby the coolanthas a narrower passageway (not shown) into the coolant coils 18, andaccordingly performs its requisite cooling function. The electricaleffect of this upward movement of arm 30 is indicated by virtue oftoggle switch arm 34 moving from terminal 34b to terminal 34a in FIG. 7.This breaks the operating circuit for the activation of hot gas solenoid32, said circuit having been traceable froma source of positivepotential over closed switch 60, terminal 64, conductor 78, arm 34,terminal 34b, conductor 80, terminal 84, and solenoid 32 to a source ofnegative potential.

The water solenoid 54 is also deactivated at this time by the sameupward movement of the arm 30 referred to immediately above. When thetoggle switch 34 returns to its up" position, the arm 34 (FIG. 7) breaksthe circuit previously traced out through hot gas solenoid 32; this sameinterruption serves also to deactivate water solenoid 54 which had beenenergized over the same circuit path up to terminal 34band thencethrough water solenoid 54 also to a negative potential source.

Water pump motor 28 had, up to this time, been deactivated, thustemporarily halting the water recirculation system. However, when theassembly 20 is returned to the horizontal position indicated in FIG. 4,the upward positioning of toggle switch 34, indicated in FIG. 7 by thecontacting of terminal 34a by arm 34, recommences the waterrecirculation by virtue of activating water pump motor 28. The circuitfor activating water pump motor 28 is traceable from the source ofnegative potential through the pump motor 28, and thence acrossconductor 82, terminal 34a, arm 34 in the up position, conductor 78,terminal 64, and through closed switch 60 to the source of positivepotential. When the pump motor 28 is thusly reactivated, it begins tocirculate water from reservoir 22 through conduit 46 and out from thepump 28 through pipe 48 into the recirculation chamber 44. Continuouspumping action during the ice cube making cycle drives the recirculatedwter from the recirculing chamber 44 and into each of the plurality ofoval shaped header tubes 52 (see FIGS. 2, and 6). Since the header tubes52 are plugged at their right-hand ends (see plug element 53 in FIG. 5),the water is driven upward from the header tubes 52 and into the variousice cube freezing receptacles 19, as indicated by the arrows in thereceptacles 19 in FIG. 4. As a result of such upward forcing of therecirculated water, freezing commences on the interior top and sidewalls of the receptacles 19. As pre- ,..viously mentioned, a great dealof this upwardly directed water spray begins to freeze immediately;however, the portion of water which does not so freeze at the outset isretained in the recirculation system by virtue of dropping throughorifices 24b (FIGS. 2 and 6) and thence into the reservoir 22 of theassembly 20. Continued recirculation in this manner causes ice togradually build up within each of the receptacles 19, thereby formingthe desired ice cubes.

As the ice cubes are so formed, the temperature in the vicinity of theice cube forming receptacles 19 is continuously reduced. For example,when the ice cube making cycle commences, atypical illustrativetemperature in this vicinity is approximately 45 Fahrenheit (F.)However, as the ice cube making cycle nears its completion, with icecubes almost fully formed in all of the receptacles 19, a typicalillustrative temperature in the vicinity thereof is approximately 32 F.By appropriate adjustment of thermostatic controls 56 and 94,recognition of such temperature reduction by the thermostatic feeler 58(and similar elements, not shown, for control 94) is arranged to triggercontrol 56. (While control 56 directly controls the positioning ofstorage assembly by controlling actuator motor 70, cycle control 94 isalso thermostatically responsive to set the overall temperature limitson the ice cube making and harvesting cycles. Thus, control 94 canillustratively be set at temperatures between 0 F. and 55 F. todetermine the cycle durations in conjunction with control 56.) Thisrecognition in effect signals the end ofthe ice cube making cycle andthe commencement ofthe harvesting" cycle.

2. Harvesting Cycle It will be recalled that once the predetermined lowor relatively cold condition is recognized by a thermostaticallycontrolled switch 56 and its associated feeler 58 and by secondthermostatically controlled switch 94, harvesting of the ice cubes willcommence by the lowering of storge tank and plate assembly 20, therebyremoving plate 24 as the bottom closure of the ice cube receptacles l9and permitting the ice cubes therein to fall by gravity once they aredislodged as described below.

This lowering of the assembly 20 occurs, with reference to FIG. 7, whenrepresentative switch arm 56 closes to the cold position represented byterminal 56b, and when thermostatic motor control arm 94 contacts itscold position terminal 94a. Since toggle switch 42, including arms 42aand 42b, is inits right position, a circuit is completed by the closureof arm 56 to terminal 56c and of arm 94 to terminal 940 to energize thelowering mechanism ofactuator motor 70. Specifically, this circuit istraceable from a positive potential source through closed switch 60,terminal 64, conductor 66,

terminal 56a, arm 56, terminal 56b, terminal 94a, arm 94, terminal 84,conductor 86, arm 42b, terminal 720, terminal 700, a lowering winding(not shown) of actuator motor 70, terminal b, and over conductor 76 to asource of negative potential. The assembly 20 is thus caused to lower,with bracket 57 pivoting around pin 53 on mounting plate 51 (FIGS. 3 and4); the assembly 20 then drops from the horizontal position shown inFIG. 4 to the inclined position indicated in FIG. 3 under the control ofmotor 70. When this inclined position has been reached, it is noted thatspring 38 is extended between pin 43 and connecting link 36. Arm 39,which is rigid with link 36, rotates about in a counterclockwise mannerand deflects toggle switch 42 to deactivate the actuator motor 70 whenthe assembly 20 has reached the appropriate inclined position.Electrically, the toggle switch 42 and its associated arms 42a and 42bare thereupon switched to the left-hand positions, thereby de-energizingthe lowering winding (between terminals 70b and 700) of actuator motor70. Accordingly, the motor 70 is temporarily de-energized. The raisingwinding (between terminals 70a and 70c) is, however, not energized sincethere is no positive potential path connected to terminal 70a.

As the assembly 20 drops to the position shown in FIG. 3, slotted member31 no longer-urges collar 33 on arm 30 upwardly. Accordingly,spring-loaded toggle switch 34 is switched to its lower position. Thisswitching of arm provides a locking operating path for the hot gassolenoid 32, which path is independent of the positions of thermostaticarms 56 and 94. As previously mentioned, this solenoid acts as a. valveand serves to widen the passageway (not shown) ofthe coolant to thecoolant coils 18 ofthe evaporator assembly 16. As a result of suchvalve-type unblocking the coolant (e.g., Freon l2, Freon 22, or othersuitable refrigerant) actually acts as a heating agent within the samecoils 18. As this hot gas passes through the coils 18, a slight meltingaction takes place within each of the ice cube receptacles 19, therebytending to dislodge the ice cubes previously formed therein during theice cube making cycle. As shown in FIG. 3, the ice cubes then drop fromthe receptales 19 onto the inclined plate 24, and thence, as shown bythe illustrative dropping ice cubes 14, into the bin 12 shown infragmentary form in FIG. 3 (see FIG. 1). From an electrical standpoint,as indicated in FIG. 7, the depressing of spring-loaded toggle switch 34drops arm 34 in FIG. 7 from terminal 34a to terminal 34b. This seves toprovide a locking path to activate the hot gas solenoid 32 over the pathfrom positive potential and across closed switch 60, terminal 64,conductor 78, arm 34, terminal 34b, conductor 80, terminal 84, andthrough hot gas solenoid 32to negative potential.

Although the machine of the present invention makes an extremelyefficient use of water which does not initially freeze in thereceptacles l9, and of water applied to the plate 24 for de-icingpurposes, there is still a need to permit a given charge of supply waterto periodically enter the system. This occurs also in response to thelowering of the assembly 20 and the accompanying deflection of toggleswitch 34 by arm 30. Water solenoid 54 is thereby activating to allowthe supply water to enter (supply not shown) into connecting pipe 55 andthrough header 50 to'deposit the water along the width of the uppersurface of plate 24. This water serves a dual function in that it bothcleans the plate 24 of any ice thereon, and is also retained by thesystem both through the recapturing orifices 24b (FIG. 6) and by catchbasin 26. Thus, all of the water which is introduced into this systemunder the control of water solenoid 54 ultimately finds its way toreservoir 22- in the assembly 20. In addition, due to the efficientwater-retaining techniques of the present invention, eliminatingwasteful drainage, the solenoid 54 can be adjusted to permit a muchsmaller charge of water to be introduced into the system than in priorart machines. Illustratively, the water charge utilized by the machineof this invention is as low as one-half that required by the prior art.

The water solenoid 54 is activated over an electrical path practicallyidentical to that which activated hot gas solenoid 32. Thus, the pathincludes positive poten-' tial, closed switch 60, terminal 64, conductor78, arm 34, terminal 34b, and through the water solenoid 54 to negativepotential. With the assembly 20 in its lower, inclined position, asshown in FIG. 3, the harvesting of the ice cubes 14 within thereceptacles l9 continues with hot gas being forced into the coils 18under the influence of hot gas solenoid 32, and a predetermined chargeof water being supplied to the system under the control of watersolenoid 54. The thermostatic controls 5.6 and 94 are adjusted so thatwhen a predetermined relatively high temperature is reached in thevicinity of the evaporator assembly I6, all the ice cubes 14 will havebeen dislodged from their partitions l9 and harvested into the bin 12.This temperature can also be determined by a few practice or trail runsof the system, and is generally around 45 F. When the control 56,through its thermostatic feeler 58 (and corresponding equipment, notshown, for control 94), recognizes that this relatively highertemperature has been reached,

controls 56 and 94 switch positions (see FIG. 7) and thereby effectivelyterminate the harvesting cycle. Referring to FIG. 7, when thermostaticcontrol 56 recognizes this end-of-harvesting condition, its arm 56 movesaway from contact 56b and comes into contact with terminal 560;similarly, arm 94 breaks away from terminal 94a and contacts terminal94b. Initially, this prevents the application of positive potential tosolenoids 32 and 54, although there is still positive potential forthese elements by virtue of the position of arm 34. Positive potentialis applied to the raising winding of actuator motor 70 between terminals70a and 70b over a path through closed switch 60, terminal 64, conductor66, terminal 560, arm 56, terminal 56c, conductor 74, arm 42a, terminal72a, terminal 70a, the raising winding of actuator motor 70, terminal70b, and through conductor 76 to negative potential. The assembly 20thus begins to raise from the position shown in FIG. 3 to that shown inFIG. 4. When the position shown in FIG. 4 has been reached, toggleswitch 34 is switched back to its up position in contact with terminal34a (FIG. 7), and self-controlled toggle switch 42 is switched to itsright-hand position, the latter serving to remove positive potentialfrom the raising winding of actuator motor 70. Moreover, since there isno positive potential at this time at terminal 720 (due to the up"positioning of arm 34 and the respective positions of controls 56 and94), the actuator motor 70 remains de-energized.

In addition, the upward movement of arm 34 from terminal 34b to terminal34a now serves to de-energize both hot gas solenoid 32 and watersolenoid 54. This permits the refrigerant to perform its coolingfunction in the cooling coils l8 and terminates the introduction of thesupply charge of water, respectively. Finally, the water pump motor 28is reactivated so as to begin the flow of water from the relatively coolsupply in reservoir 22 to recirculating chamber 44 and header tubes 52,thus recommencing the ice cube making cycle as previously described.

It is of course understood that additional instrumentation can beprovided to furnish additional sophisti cated controls within the skillof the art. For example, switch 90, which can be representative of asolenoid or other similar switch arrangement, can provide suitablepressure or manual safety control for the compressor or condensing unit88 connected in series therewith. Similarly, switch 60 which is normallyclosed during both cycles described above, can be connected by means ofa feeler 62 (FIGS. 1, 3 and 4) disposed within bin 12 to prevent excessaccumulation and freezing together of the dislodged and harvested icecubes therein. It is apparent that if switch or solenoid 60 opens thecircuit next to its associated positive potential source, neither of thecycles previously described could take place.

Additional instrumentation can include wash switch 92 which is normallyclosed, but which can be opened manually to deactivate compressor 88 topermit, for example, sevicing of the system. Manual control of supplywater can be achieved by means of switch 96, which, when closed, permitssupply water to enter the system by activating water solenoid 54 whenswitch 34 is in contact with terminal 34a. This is accomplished over apath from positive potential and closed switch 60 and including terminal64, conductor 78, arm 34, terminal 34a, conductor 98, now closed switch96,'terminal 84, conductor 80, and through water solenoid 54 to negativepotential. Other suitable instrumentation will be apparent to thoseskilled in the art to achieve various functional controls.

From the foregoing, it will be appreciated that the present inventionfinds it application in an automatic ice cube making machine of the typehaving a freezing cycle and a harvesting cycle and including anevaporator and freezer assembly 16 providing a cube-freezing chamberhaving a plurality of open bottom individual cells 19 disposed in heatexchange relationship with the coils 18 on the upper surface or wall 17of the assembly 16. The storage tank and plate assembly 20 including topplate 24 provide a closure which is movable into a cell-closing positionin which the closure substantially closes the open bottom of theplurality of cells 19 of the freezing chamber during the freezing cycle(see FIG. 4) and into a cube-discharge position in which the closureopens the bottom of the plurality of cells during the operable inconjunction with a two-position switch,

vated drive 70 for moving the closure into the cellclosing position ofFIG. 4 and a second energization circuit to move the closure into thecube-discharge position of FIG. 3. The temperature-responsive controlfor initiating and terminating the freezing and harvesting cyclesincludes a first thermostatically activated switch 56 which isresponsvlee to the temperature of the evaporator and freezer assembly orunit 16 and is operable in a first switch positon bridging contacts 56aand 56c and at a predetermined temperature to complete the firstenergization circuit from the source over toggle switch contacts 420,72a to the drive for moving the closure to the cell-closing position.The first thermostatically activated switch 56 is operable over contacts56a, 56b to initiate the freezing cycle and is responsive to a drop intemperature of the evaporator unit 16 to condition the control forinitiating the start of the harvesting cycle. The control furtherincludes the second thermostatically activated switch 94 which likewiseis responsive to the temperature of the evaporator nit 16 and isoperable at a lower predetermined temperature for initiating theharvesting cycle. Specifically, the second thermostatically activatedswitch 94 is operable at the lower predetermined temperature to completethe second energization circuit from the source to the electricallyactivated drive 70 for moving the closure to the cube-dischargeposition. Finally, the first thermostatically activated switch 56 isresponsive to a rise in temperature of the evaporator unit 16 toterminate the harvesting cycle and to initiate the start of anotherfreezing cycle.

It is to be understood that the above-described arrangements areillustrative of the application of the principles of the invention.Numerous other arrangements may be devised by those skilled in the artwithout departing from the spirit and scope of the invention.

What is claimed is:

l. A machine for making ice cubes and having an ice cube making and anice cube harvesting cycle comprising a collection bin for receiving saidice cubes, a freezing chamber for containing said ice cubes during saidice cube making cycle, an evaporator assembly in heat exchangingrelation with said freezing chamber, storage assembly means including areservoir for circulated water furnished to said freezing chamber duringsaid ice cube making cycle and for supply water furnished to saidmachine during said ice cube harvesting cycle including plate means foracting as a bottom closure for said freezing chamber during said icecube making cycle, water transporting means for circulating water tosaid freezing chamber, temperature responsive control means comprisingfirst and second thermostatically actuated switches responsive tothedetection of a first predetermined relatively lower temperature insaid freezing chamber for terminating said ice cube making cycle andresponsive to the detection of a second predetermined relatively highertemperature in said freezing chamber for terminating said ice cubeharvesting cycle and driving means responsive to said control meansdetecting said first predetermined relatively lower temperature forpositioning said storage assembly means whereby said plate means directssaid ice cubes dislodged from said freezing chamber into said collectionbin during said ice cube harvesting cycle and responsive to said controlmeans detecting said second predetermined relatively higher temperaturefor positioning said storage assembly means whereby said plate meanssaid bottom closure position relative to said freezing chamber duringsaid ice: cube making cycle.

2. A machine in accordance with claim l wherein said evaporator assemblyincludes a coil network for carrying a heat exchanging substance andincluding in addition heat exchange supervisory means responsive to saidcontrol means detecting said second predetermined relatively highertemperature for directing said substance into said coil network as acoolant during said ice cube making cycle and responsive to said controlmeans detecting said first predetermined relatively lower temperaturefor directing said substance into said coil network as a heating agentduring said ice cube harvesting cycle. v

3. A machine in accordance with claim 1 wherein said freezing chamberincludes a plurality of inverted receptacles and an upper surface forsupporting said evaporator assembly, wherein said plate means includes aplurality of apertures grouped to correspond with each of saidreceptacles, and wherein said water transporting means includes arecirculation chamber, a plurality of header tubes communicating withsaid recirculating chamber and with said receptacles through a firstgroup of said apertures during said ice cube making cycle, and a pumpresponsive to the commencement of said ice cube making cycle fordelivering water from said reservoir to said receptaclesthrough saidrecirculation chamber and said header tubes, whereby said water isforced through said first group of apertures and substantial quantitiesofsaid water adheres in freezing relation to the interior of saidreceptacles, the remainder of said forced water being recaptured by asecond group of said apertures for return to said reservoir.

4. A machine in accordance with claim 1 wherein said plate meansincludes plural recapturing orifices therethrough, including in additionwater supply control means for introducing a predetermined charge ofsupply water into said water transporting means during said ice cubeharvesting cycle, including means for depositing said charge of supplywater onto said plate means for de-icing said plate means, wherein saidstorage assembly means includes catch basin means projecting beyond theend of said plate means for directing said supply water to saidreservoir, whereby a portion of said charge of supply water enters saidreservoir through said recapturing orifices and the remainder of saidcharge of supply water enters said reservoir through said catch basinmeans.

5. A machine in accordance with claim 2 wherein said control meansincludes at least one thermostatic unit having a feeler elementresponsive to the heating action of said heat exchanging substanceduring said ice cube harvesting cycle for energizing said driving meansto elevate said storage assembly means whereby said plate means isbrought into a closure relation with said evaporator assembly toterminate the introduction of said heat exchanging substance as acoolant, and responsive to the cooling action of said heat exchangingsubstance during said ice cube making cycle for energizing said drivingmeans to lower said storage assem bly means whereby said plate means isremoved from said closure relation with said evaporator assembly toterminate the introduction of said heat exchanging substance as aheating agent.

6. An automatic ice cube making machine of the type including a freezingchamber having a plurality of open bottom individual cells in heatexchange relation with a refrigerant evaporator; a closure plate movablebe tween a cell-closing position whereby the closure plate substantiallycloses the open bottom of said plurality of cells during the freezingcycle of the evaporator and an ice cube discharge position whereby theclosure plate opens the bottom of the plurality of cells during theharvest cycle of the machine; motor means for moving said closure platebetween cell-closure position and ice cube discharge position; tankmeans for holding a volume of water substantially equal to the volume ofwater required for producing the ice cubes, supply means for controllingthe supply of water to said tank; recirculation means for recirculatingthe water in said tank through the plurality of cells during saidfreezing cycle; a source of potential; and control means responsive to apredetermined temperature in said freezing chamber for terminating thefreezing cycle of said evaporator and connecting said source ofpotential across said motor means to energize said motor means to movesaid closure plate to said ice cube discharge position,

wherein said control means'includes a first thermostatically actuatedswitch connected to said source of potential and a secondthermostatically controlled switch serially connected between said firstthermostatically controlled switch and said motor means, whereby saidfirst thermostatically controlled switch connects said source ofpotential across said second thermostatically controlled switch when thetemperature in said freezing chamber reaches a first temperature abovesaid predetermined temperature, and said second thermostaticallycontrolled switch connects said source of potential across said motormeans when the temperature in said freezing chamber reaches saidpredetermined temperature.

7. In an automatic ice cube making machine of the type having a freezingcycle and harvesting cycle and including an evaporator unit, acube-freezing chamber having a plurality of open'bottom individual cellsdisposed in heat exchange relation with said evaportor unit, a closuremovable into a cell-closing position in which said closure substantiallycloses the open bottom ofsaid plurality of cells of said freezingchamber during said freezing cycle and into a cube-discharge position inwhich said closure opens the bottom of the plurality of cells duringsaid harvest in cycle and an electrically activated drive for movingsaid closure between said cell-closing and cube-discharge positions, theimprovement comprising a temperature-responsive control for initiatingand terminating said freezing and harvesting cycles comprising a sourceof potential, a first thermostatically activated switch responsive tothe temperature of said evaporator unit and operable in a first switchposition to connect said drive to said source for moving said closure tosaid cell-closing position to start said freezing cycle, said firstthermostatically activated switch being responsive to a drop intemperature of said evaporator unit and operable in a second switchposition to condition said control for the initiation of the start ofsaid harvesting cycle and a second thermostatically activated switchresponsive to the temperature of said evaporator unit and operable toinitiate said harvesting cycle, said first thermostatically activatedswitch being responsive to a rise in temperature of said evaporator unitto initiate the start of the next freezing cycle.

8. In an automatic ice cube making machine according to claim 7, a watersupply, means for circulating water from said supply over said closureand means operable in response to movement of said closure into and outof said cell-closing position for controlling the circulation of waterfrom said supply to said closure.

9. In an automatic ice cube making machine according to claim 8, saidcontrolling means being arranged to interrupt the supply of water tosaid freezer chamber when said closure is in said cell-closing position.

10. In an automatic ice cube making machine according to claim 7, a hotgas supply and means operable under control of said secondthermostatically activated switch for controlling the flow of hot gasfrom said hot gas supply into heat exchange relation to freezingchamber.

11. In an automatic ice cube making machine according to claim 10, saidcontrolling means being arranged to initiate flow of hot gas into heatexchange to said freezing chamber under control of said secondthermostatically activated switch and when said closure is in saidcube-discharge position.

12. In an automatic ice cube making machine of the type having afreezing cycle and a harvesting cycle, an evaporator unit, acube-freezing chamber having a plurality of open bottom individual cellsdisposed in heat exchange relation with said evaporator unit, a closuremovable into a cell-closing position in which said closure substantiallycloses the open bottom of said plurality of cells of said freezingchamber during said freezing cycle and into a cube-discharge position inwhich said closure opens the bottom of the plurality of cells duringsaid harvest cycle, a source of potential, an electrically activateddrive for moving said closure between said cell-closing andcube-discharge position, a twoposition switch actuated in response tomovement of said closure between said cell-closing and cubedischargepositions for establishing a first energization circuit between saidsource and said drive to move said closure into said cell-closingposition and a second energization circuit from said source to saiddrive to move said closure into said cube-dischargbe position and atemperature-responsive control for initiating and terminating saidfreezing and harvesting cycles including a first thermostaticallyactivated switch responsive to the temperature of said evaporator unitand operable in a first switch position and at a predeterminedtemperature to complete said first energization circuit from said sourceto said drive for moving said closure to said cell-closing position,said first thermostatically activated switch being operable to initiatesaid freezing cycle and being responsive to a drop in temperature ofsaid evaporator unit and operable in a second switch position tocondition said temperature-responsive control for the initiation ofthestart of said harvesting cycle and a second thermostatically activatedswitch responsive to the temperature of said evaporator unit andoperable at a lower predetermined temperature for initiating saidharvesting cycle, said second thermostatically activated switch beingoperable at said lower predetermined temperature to complete said secondenergization circuit from said source to said drive for moving saidclosure to said cube-discharge position, said first thermostaticallyactivated switch being responsive to a rise in the temperature of saidevaporator unit to terminate said harvesting cycle and to initiate thestart of another freezing cycle.

13. In an automatic ice cube making machine according to claim 12, awater supply, means for depositing water from said supply onto saidclosure and means operable in respnose to movement of said closure intosaid cube-discharge position for initiating the supply of to terminatethe supply of water onto said closure.

15. In an automatic ice cube making machine according to claim 12, a hotgas supply and means operable under control of said secondthermostatically activated switch for initiating the flow of hot gasfrom said hot gas supply into heat exchange relation to freezing chamberat the start of said harvesting cycle.

l l l =l l

1. A machine for making ice cubes and having an ice cube making and anice cube harvesting cycle comprising a collection bin for receiving saidice cubes, a freezing chamber for containing said ice cubes during saidice cube making cycle, an evaporator assembly in heat exchangingrelation with said freezing chamber, storage assembly means including areservoir for circulated water furnished to said freezing chamber duringsaid ice cube making cycle and for supply water furnished to saidmachine during said ice cube harvesting cycle including plate means foracting as a bottom closure for said freezing chamber during said icecube making cycle, water transporting means for circulating water tosaid freezing chamber, temperature responsive control means comprisingfirst and second thermostatically actuated switches responsive to thedetection of a first predetermined relatively lower temperature in saidfreezing chamber for terminating said ice cube making cycle andresponsive to the detection of a second predetermined relatively highertemperature in said freezing chamber for terminating said ice cubeharvesting cycle and driving means responsive to said control meansdetecting said first predetermined relatively lower temperature forpositioning said storage assembly means whereby said plate means directssaid ice cubes dislodged from said freezing chamber into said collectionbin during said ice cube harvesting cycle and responsive to said controlmeans detecting said second predetermined relatively higher temperaturefor positioning said storage assembly means whereby said plate meanssaid bottom closure position relative to said freezing chamber duringsaid ice cube making cycle.
 2. A machine in accordance with claim 1wherein said evaporator assembly includes a coil network for carrying aheat exchanging substance and including in addition heat exchangesupervisory means responsive to said control means detecting said secondpredetermined relatively higher temperature for directing said substanceinto said coil network as a coolant during said ice cube making cycleand responsive to said control means detecting said first predeterminedrelatively lower temperature for directing said substance into said coilnetwork as a heating agent during said ice cube harvesting cycle.
 3. Amachine in accordance with claim 1 wherein said freezing chamberincludes a plurality of inverted receptacles and an upper surface forsupporting said evaporator assembly, wherein said plate means includes aplurality of apertures grouped to correspond with each of saidreceptacles, and wherein said water transporting means includes arecirculation chamber, a plurality of header tubes communicating withsaid recirculating chamber and with said receptacles through a firstgroup of said apertures during said ice cube making cycle, and a pumpresponsive to the commencement of said ice cube making cycle fordelivering water from said reservoir to said receptacles through saidrecirculation chamber and said header tubes, whereby said water isforced through said first group of apertures and substantial quantitiesof said water adheres in freezing relation to the interior of saidreceptacles, the remainder of said forced water being recaptured by asecond group of said apertures for return to said reservoir.
 4. Amachine in accordance with claim 1 wherein said plate means includesplural recapturing orifices therethrough, including in addition watersupply control means for introducing a predetermined charge of supplywater into said water transporting means during said ice cube harvestingcycle, including means for depositing said charge of supply water ontosaid plate means for de-icing said plate means, wherein said storageassembly means includes catch basin means projecting beyond the end ofsaid plate means for directing said supply water to said reservoir,whereby a portion of said charge of supply water enters said reservoirthrough said recapturing orifices and the remainder of said charge ofsupply water enters said reservoir through said catch basin means.
 5. Amachine in accordance with claim 2 wherein said control means includesat least one thermostatic unit having a feeler element responsive to theheating action of said heat exchanging substance during said ice cubeharvesting cycle for energizing said driving means to elevate saidstorage assembly means whereby said plate means is brought into aclosure relation with said evaporator assembly to terminate theintroduction of said heat exchanging substance as a coolant, andresponsive to the cooling action of said heat exchanging substanceduring said ice cube making cycle for energizing said driving means tolower said storage assembly means whereby said plate means is removedfrom said closure relation with said evaporator assembly to terminatethe introduction of said heat exchanging substance as a heating agent.6. An automatic ice cube making machine of the type including a freezingchamber having a plurality of open bottom individual cells in heatexchange relation with a refrigerant evaporator; a closure plate movablebetween a cell-closing position whereby the closure plate substantiallycloses the open bottom of said plurality of cells during the freezingcycle of the evaporator and an ice cube discharge position whereby theclosure plate opens the bottom of the plurality of cells during theharvest cycle of the machine; motor means for moving said closure platebetween cell-closure position and ice cube discharge position; tankmeans for holding a volume of water substantially equal to the volume ofwater required for producing the ice cubes, supply means for controllingthe supply of water to said tank; recirculation means for recirculatingthe water in said tank through the plurality of cells during saidfreezing cycle; a source of potential; and control means responsive to apredetermined temperature in said freezing chamber for terminating thefreezing cycle of said evaporator and connecting said source ofpotential across said motor means to energize said motor means to movesaid closure plate to said ice cube discharge position, wherein saidcontrol means includes a first thermostatically actuated switchconnected to said source of potential and a secOnd thermostaticallycontrolled switch serially connected between said first thermostaticallycontrolled switch and said motor means, whereby said firstthermostatically controlled switch connects said source of potentialacross said second thermostatically controlled switch when thetemperature in said freezing chamber reaches a first temperature abovesaid predetermined temperature, and said second thermostaticallycontrolled switch connects said source of potential across said motormeans when the temperature in said freezing chamber reaches saidpredetermined temperature.
 7. In an automatic ice cube making machine ofthe type having a freezing cycle and harvesting cycle and including anevaporator unit, a cube-freezing chamber having a plurality of openbottom individual cells disposed in heat exchange relation with saidevaportor unit, a closure movable into a cell-closing position in whichsaid closure substantially closes the open bottom of said plurality ofcells of said freezing chamber during said freezing cycle and into acube-discharge position in which said closure opens the bottom of theplurality of cells during said harvest in cycle and an electricallyactivated drive for moving said closure between said cell-closing andcube-discharge positions, the improvement comprising atemperature-responsive control for initiating and terminating saidfreezing and harvesting cycles comprising a source of potential, a firstthermostatically activated switch responsive to the temperature of saidevaporator unit and operable in a first switch position to connect saiddrive to said source for moving said closure to said cell-closingposition to start said freezing cycle, said first thermostaticallyactivated switch being responsive to a drop in temperature of saidevaporator unit and operable in a second switch position to conditionsaid control for the initiation of the start of said harvesting cycleand a second thermostatically activated switch responsive to thetemperature of said evaporator unit and operable to initiate saidharvesting cycle, said first thermostatically activated switch beingresponsive to a rise in temperature of said evaporator unit to initiatethe start of the next freezing cycle.
 8. In an automatic ice cube makingmachine according to claim 7, a water supply, means for circulatingwater from said supply over said closure and means operable in responseto movement of said closure into and out of said cell-closing positionfor controlling the circulation of water from said supply to saidclosure.
 9. In an automatic ice cube making machine according to claim8, said controlling means being arranged to interrupt the supply ofwater to said freezer chamber when said closure is in said cell-closingposition.
 10. In an automatic ice cube making machine according to claim7, a hot gas supply and means operable under control of said secondthermostatically activated switch for controlling the flow of hot gasfrom said hot gas supply into heat exchange relation to freezingchamber.
 11. In an automatic ice cube making machine according to claim10, said controlling means being arranged to initiate flow of hot gasinto heat exchange to said freezing chamber under control of said secondthermostatically activated switch and when said closure is in saidcube-discharge position.
 12. In an automatic ice cube making machine ofthe type having a freezing cycle and a harvesting cycle, an evaporatorunit, a cube-freezing chamber having a plurality of open bottomindividual cells disposed in heat exchange relation with said evaporatorunit, a closure movable into a cell-closing position in which saidclosure substantially closes the open bottom of said plurality of cellsof said freezing chamber during said freezing cycle and into acube-discharge position in which said closure opens the bottom of theplurality of cells during said harvest cycle, a source of potential, anelectrically activated drive for moving said closure between saidcell-closing aNd cube-discharge position, a two-position switch actuatedin response to movement of said closure between said cell-closing andcube-discharge positions for establishing a first energization circuitbetween said source and said drive to move said closure into saidcell-closing position and a second energization circuit from said sourceto said drive to move said closure into said cube-dischargbe positionand a temperature-responsive control for initiating and terminating saidfreezing and harvesting cycles including a first thermostaticallyactivated switch responsive to the temperature of said evaporator unitand operable in a first switch position and at a predeterminedtemperature to complete said first energization circuit from said sourceto said drive for moving said closure to said cell-closing position,said first thermostatically activated switch being operable to initiatesaid freezing cycle and being responsive to a drop in temperature ofsaid evaporator unit and operable in a second switch position tocondition said temperature-responsive control for the initiation of thestart of said harvesting cycle and a second thermostatically activatedswitch responsive to the temperature of said evaporator unit andoperable at a lower predetermined temperature for initiating saidharvesting cycle, said second thermostatically activated switch beingoperable at said lower predetermined temperature to complete said secondenergization circuit from said source to said drive for moving saidclosure to said cube-discharge position, said first thermostaticallyactivated switch being responsive to a rise in the temperature of saidevaporator unit to terminate said harvesting cycle and to initiate thestart of another freezing cycle.
 13. In an automatic ice cube makingmachine according to claim 12, a water supply, means for depositingwater from said supply onto said closure and means operable in respnoseto movement of said closure into said cube-discharge position forinitiating the supply of water onto said closure.
 14. In an automaticice cube making machine according to claim 13, including means operableunder control of said second thermostatically activated switch toterminate the supply of water onto said closure.
 15. In an automatic icecube making machine according to claim 12, a hot gas supply and meansoperable under control of said second thermostatically activated switchfor initiating the flow of hot gas from said hot gas supply into heatexchange relation to freezing chamber at the start of said harvestingcycle.